Sitting in the stands at Ewood Park was his old Wolfsburg manager Steve McClaren, who has been telling anyone who cares to listen that the man who terrorised the Bundesliga for two and a half seasons will come good.

McClaren’s prophecy came good on 75 minutes when Dzeko was Johnny-on-the-spot to lash home his fifth City goal, just three minutes after coming on as a substitute.

With Carlos Tevez injured, and Mario Balotelli retreating into his shell, Dzeko had been called from the bench to pep up a City side who began like world-beaters but then were dragged into a tough scrap by plucky Rovers.

Roberto Mancini had the rare advantage of being able to name an entirely unchanged 18 from the players who beat Manchester United at Wembley just nine days earlier.

Not that he had a lot of choice, with Tevez, Micah Richards and Jerome Boateng all unavailable.

And for 20 minutes City were unchanged in terms of their vitality and positivity, as well.

They were surging with confidence and adrenalin, the natural consequence of those memorable events at Wembley.

The passing was crisp and quick, the movement was excellent and poor Blackburn were being opened up like a rusty tin can.

As early as the third minute the Blues should have been ahead as Pablo Zabaleta found space down the right and pulled the ball back for Gareth Barry.

His attempted control took the ball into the path of David Silva, who crashed a volley against the inside of the post.

Moments later Adam Johnson skinned Gael Givet and crossed, two defenders lunging in to stop the ball reaching the unmarked Mario Balotelli.

City looked unstoppable, with Silva and Yaya Toure dropping deep to pick up the ball and then probe for openings.

With Aleks Kolarov and Zabaleta both ranging down the flanks, the options were limitless – the only problem was that Balotelli was not alive to the possibilities, or was well policed by Phil Jones and Chris Samba in his lone striker role.

Such was City’s dominance that the ball barely touched their half for the opening quarter of the game – Joe Hart did not get a touch for 14 minutes.

Barry got his head to a near-post corner only for Michel Salgado to clear off the line.

City doubt

It was at that point that a little anxiety began to creep in, and possibly a touch of self-doubt.

When you have established such a grip, and failed to score, it crosses the mind that it might not happen, and City appeared to have a spell of that negative thinking.

Not only that, Blackburn began to squeeze the space between their midfield and defence, and Silva and Yaya had less space in which to operate.

Misplaced passes began to creep in, and Rovers – fighting for their lives at the bottom – began to grow in confidence and ambition themselves.

Big defender Chris Samba came closest for the home side, rising above the City defence to head inches wide of the post from Salgado’s clever chip.

Blackburn, incredibly, ended the half on the up, and Mancini had his full complement of subs warming up as a warning to his team that they needed to regain their composure.

Half time gave the manager the chance to drill that message home, and it appeared to work as Silva’s chip to the far post found Yaya, and his header brought a flying save from Paul Robinson.

But Rovers had a sniff of a chance of three vital points, and they had lost their early respect for the Blues.

Martin Olsson had half of the ground celebrating when he volleyed into the side netting after Jason Roberts had only managed to head across the face of goal.

At a time when City needed to see the best of Balotelli, we began to see the worst.

He was disappearing deeper and deeper, and hiding out on the left flank – and then he picked up yet another silly booking for a needless swipe at Gael Givet.

It all looked like it was going the shape of the pear, but Mancini acted by bringing on Dzeko, to tremendous effect.

It was Barry who made the difference, surging down the left and pulling the ball back for Silva.

For once the little Spaniard simply swiped the ball into the danger area without subtlety, but it bounced off Phil Jones and landed at Dzeko’s feet.

He swept it in for a great personal moment, and a vital goal, all the frustration of the past three months channelled through the swipe of his right boot.

There was still plenty of hard defending to do, but City are made of stern stuff these days. The defence stood firm and Hart, secure under all the high balls, beat away Martin Olsson’s free kick as Rovers pressed for the equaliser.